This invention relates to apparatus for monitoring temperature dependent changes and is specifically applicable to melting point determining apparatus. Such apparatus conventionally comprises a heating arrangement, or oven, for heating solids within a transparent sample tube up to a temperature of, for example, 350.degree. C. Internal illumination is provided to allow the melting process to be seen through a lens. Temperature measuring means are provided to give a display of temperature which display may be held, by means of a switch, when the melting point is seen. Such apparatus could equally monitor other physical and/or chemical changes such as sublimation and viscosity changes.
Various aspects of the present invention are intended to improve such apparatus, for example by reducing its casing temperature, simplifying its internal structure and making it more convenient to operate.